Gravitational Waves Detected for the First Time

The Discovery of a Lifetime

Gravitational waves, first theorized by Albert Einstein in his theory of relativity, have been detected by physicists for the first time. Caused by the collision of two massive black holes, ripples in space-time called gravitational waves, were sent through the universe at the speed of light until they were detected by physicists at the LIGO observatory on September 14, 2015.

The collision of two black holes thirty times the mass of our sun sent out ripples strong enough to be detected by researchers on earth, about 1.3 billion light years away. Because of its distance from earth, the collision occurred about 1.3 billion years ago, and was just recently detected late last year. “It is by far the most powerful explosion humans have ever detected except for the big bang,” says Kip Thorne, a physicist from Caltech who cofounded the LIGO project.

After verifying the data received from LIGO for five months, physicists at the Laser Interferometer Gravitational-Wave Observatory have just recently provided evidence of the existence of gravitational waves postulated by Einstein 100 years ago. The extraordinarily strong forces created by the colliding black holes were almost imperceptible on earth because of their distance and only caused the planet to stretch and expand a negligible 1/100,000th of a nanometer. These infinitesimal changes caused by gravitational waves can only be detected by the exceptionally precise sensors at LIGO.

A model of how the Laser Interferometer Gravitational-Wave Observatory uses laser light to detect gravitational waves

The Result of Decades of Work

Inspired by Joseph Weber, a pioneer of gravitational wave detection in the 1960s, LIGO was founded by scientists from MIT and Caltech to detect the expansion and contraction of space-time caused by gravitational waves. LIGO uses a combination of lasers and mirrors with its two arms, each four kilometers long, to measure minute changes in their length, only fractions of the width of a proton. Sensors called interferometers inside the LIGO observatory accurately measure these changes using laser lights that rapidly reflect back and forth in each arm. Any interference detected by the sensor will cause light to exit through a small port where physicists can measure changes caused by gravitational waves.

Eliminating any doubt of gravitational waves in the scientific community, evidence of these waves heralds a wave of new discoveries and observatories to detect these waves. This extraordinary discovery will open up a window for an entirely new area of astronomy and will allow us to observe objects in the cosmos invisible until now. “The skies will never be the same,” says astrophysicist Szabolcs Marka, a member of the LIGO research team.

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